It is often necessary to lift large, heavy objects during a manufacturing process, such as, for example, during the process of painting steel enclosures (known as "tanks") for pad mounted transformers. These large, usually rectangular tanks can be painted in an automatic paint facility using the following process, for example.
The tanks are placed one at a time onto a carrier rack that can hold up to four tanks. The carrier rack can be adapted to be carried via a conveyor system to a paint vat, into which the carrier rack is dipped along with the tanks. Preferably, the tanks are oriented on the carrier rack to allow good coverage as they pass through the painting operation. For example, the tanks can be oriented horizontally (i.e., with one of the four side faces facing downward) by placing them on horizontal arms of the carrier rack.
Typically, the tanks are delivered to the conveyor system on a towed cart. To minimize the size of the cart needed, the tanks are positioned on the cart vertically (i.e., with the top or bottom face facing downward). Thus, not only must each tank be lifted off of the cart and onto the carrier, but each tank must also be rotated by about 90 degrees at the same time. Similarly, the painted tanks must be taken from the carrier, rotated by about 90 degrees, and moved back onto the cart.
As a tank typically weighs more than 50 pounds (and frequently up to as much as 100 pounds or more), a tank is too heavy and too large for an ordinary person to move from the cart to the carrier, or vice versa, without the aid of a lifting tool. U.S. Pat. No. 6,209,938 discloses and claims a lifting tool for safe 90 degree rotation of large heavy objects.
In certain applications, however, it is necessary to rotate the object by more than 90 degrees while lifting and moving the object from one location to another. For example, in the painting process described above, the arms of the carrier rack onto which the tanks are to be placed may not be horizontal. In such circumstances, it is often necessary to rotate the tank by as much as 105 degrees during the lifting and moving process. The lifting tool described in U.S. Pat. No 6,209,938, while suitable for 90 degree rotation, is not optimal for rotation in excess of 90 degrees. Thus, there is a need in the art for a lifting tool that can aid a person in lifting and moving large, heavy objects, while rotating the objects up to 105 degrees.